Long-term evolution is the fourth generation technology of cellular networks in which the transfer rate of voice, data and video is very high. VoIP enables people to have phone conversations online. This article aims to find ways for high quality service for users, especially when the network is busy, since VoIP is a real-time service and competing over access to communication channels leads to packet or failure in packets. Hence, in cases when these parameters are higher than toleration level, the service is influenced and network congestion occurs. So, as we can infer, traffic control and service quality are connected and proportionate and an improvement in one of them improves the other. Researchers try to improve service quality parameters to control congestion. This paper focuses on end-to-end packet of voice on the internet protocol in centralized LTE networks. In order to evaluate the packet of E2E , simulation is done using NS3 tool. Three different scenarios are defined; one is network-based, one includes VoIP and the third includes VoIP with FTP . E2E packet and packet loss for every scenario has been measured. A comparative performance analysis has been simulated for both networks using output graphs; and VoIP performance in LTE has been discussed.